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Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => Wireless and Communications => Topic started by: Luke Robinson on November 15, 2016, 11:36:12 am

Title: Long distance (2500 ft) Wireless Audio Transmission
Post by: Luke Robinson on November 15, 2016, 11:36:12 am
We have a reoccurring gig each year that involves a parade of boats decorated for christmas on a river. This year we have been asked to transmit the audio from the announcer to both sides of the river. The second location is about 2500 ft from the first according to google maps.

We have clean line of sight and are elevated about 30-40 ft above the river on both sides.

Usually I use an IEM system for delay towers and the like but they seem to max out between 300 and 400 ft. I clearly need more power here.

Does anyone know of a solution for transmitting audio over this kind of distance cleanly?

Thanks,
Luke
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Tim McCulloch on November 15, 2016, 11:42:24 am
We have a reoccurring gig each year that involves a parade of boats decorated for christmas on a river. This year we have been asked to transmit the audio from the announcer to both sides of the river. The second location is about 2500 ft from the first according to google maps.

We have clean line of sight and are elevated about 30-40 ft above the river on both sides.

Usually I use an IEM system for delay towers and the like but they seem to max out between 300 and 400 ft. I clearly need more power here.

Does anyone know of a solution for transmitting audio over this kind of distance cleanly?

Thanks,
Luke

We have used Lectrosonics IFB transmitter (250mW) and appropriate Lectro receiver.  We used helical antenna on the transmit side and LPDA (paddle) antenna on the receive end.  We rent a package from Bexel Broadcast in VA (formerly the Systems Wireless shop).  Flawless performance.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Mike Pyle on November 15, 2016, 12:38:52 pm
We have a reoccurring gig each year that involves a parade of boats decorated for christmas on a river. This year we have been asked to transmit the audio from the announcer to both sides of the river. The second location is about 2500 ft from the first according to google maps.

We have clean line of sight and are elevated about 30-40 ft above the river on both sides.

Usually I use an IEM system for delay towers and the like but they seem to max out between 300 and 400 ft. I clearly need more power here.

Does anyone know of a solution for transmitting audio over this kind of distance cleanly?

Thanks,
Luke

That is within the spec for Xirium Pro, if you have the budget for it.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: David Sturzenbecher on November 15, 2016, 12:41:59 pm
That is within the spec for Xirium Pro, if you have the budget for it.

Too bad they have all been recalled.


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Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Steve Payne on November 15, 2016, 12:48:28 pm
We have a reoccurring gig each year that involves a parade of boats decorated for christmas on a river. This year we have been asked to transmit the audio from the announcer to both sides of the river. The second location is about 2500 ft from the first according to google maps.

We have clean line of sight and are elevated about 30-40 ft above the river on both sides.

Usually I use an IEM system for delay towers and the like but they seem to max out between 300 and 400 ft. I clearly need more power here.

Does anyone know of a solution for transmitting audio over this kind of distance cleanly?

Thanks,
Luke

Is price an object?  Neutrk Xirium Pro is purpose built for just this application and likely the king of the hill. Rated for up to 1/2 mile line of site transmission.  We have used this system all season (though not at this extreme distance) and it is stupid easy to set up, rock solid in performance and sounds like it's hard wired.

http://www.neutrik.us/en-us/news/xirium_pro
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Steve Payne on November 15, 2016, 12:50:34 pm
Too bad they have all been recalled.


Sent from my iPhone using Tapatalk

Yep.  Circuit boards delaminating.  They hope to have the problem solved and reshipping before end of year is what I hear.  It's a great system.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Jason Lavoie on November 15, 2016, 02:56:57 pm
We have used Lectrosonics IFB transmitter (250mW) and appropriate Lectro receiver.  We used helical antenna on the transmit side and LPDA (paddle) antenna on the receive end.  We rent a package from Bexel Broadcast in VA (formerly the Systems Wireless shop).  Flawless performance.

Any particular reason to use two different antennas?
wouldn't you want the polarization to match?

Jason
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Tim McCulloch on November 15, 2016, 04:09:47 pm
Any particular reason to use two different antennas?
wouldn't you want the polarization to match?

Jason

I had to go back and look at the invoice.  We had 2 systems, one with helical and the other with paddles.  I somehow put them together in my memory....  Damn this getting old thing is getting old.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Tim Woodworth on November 15, 2016, 04:18:16 pm
Hey Luke,

You can reach these distances by using the technique called point to point with a Shure PSM900 unit as the transmitter, and a Shure UHF-R as the receiver. We use this all of the time for large scale events that we want a wireless solution. just Google "Shure point to point" and you will find a PDF that explains how to put the PSM900 into the PTP mode. Obviously the two units must be tuned to the same frequency, so they must be in the same freq. range. Helical on the 900 and high gain paddles on the UHF-R and you will be good to go.

I hope this helps. Let me know if you have any questions.


Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Luke Robinson on November 15, 2016, 05:18:44 pm
Hey Luke,

You can reach these distances by using the technique called point to point with a Shure PSM900 unit as the transmitter, and a Shure UHF-R as the receiver. We use this all of the time for large scale events that we want a wireless solution. just Google "Shure point to point" and you will find a PDF that explains how to put the PSM900 into the PTP mode. Obviously the two units must be tuned to the same frequency, so they must be in the same freq. range. Helical on the 900 and high gain paddles on the UHF-R and you will be good to go.

I hope this helps. Let me know if you have any questions.

Sounds interesting, I am going to have to do some research, thanks for the tip that is gear that is redially available.

Does anyone know of a rental house in the Philadelphia area that may have the Lectrosonics gear. I was going to call tim's contact in VA and see if they would be willing to do a rental via UPS but if i can get it locally all the better.

Thanks to all for your help.

Luke
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Steve Payne on November 15, 2016, 05:41:51 pm
....  Damn this getting old thing is getting old.

Ain't so bad when you consider the alternative.  Keep on keeping on there, buddy.  :-)
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Elliot Carroll on November 15, 2016, 05:58:11 pm
Hey Luke,

You can reach these distances by using the technique called point to point with a Shure PSM900 unit as the transmitter, and a Shure UHF-R as the receiver. We use this all of the time for large scale events that we want a wireless solution. just Google "Shure point to point" and you will find a PDF that explains how to put the PSM900 into the PTP mode. Obviously the two units must be tuned to the same frequency, so they must be in the same freq. range. Helical on the 900 and high gain paddles on the UHF-R and you will be good to go.

I hope this helps. Let me know if you have any questions.

+1 to this, although it was a PSM1000 and UHF-R that was used.  Helical both ends to keep the pattern as tight as possible as long as possible.  Used successfully many times.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: David Sturzenbecher on November 15, 2016, 06:11:48 pm
+1 to this, although it was a PSM1000 and UHF-R that was used.  Helical both ends to keep the pattern as tight as possible as long as possible.  Used successfully many times.


I would caution blindly using this approach.  The transfer function of this setup is far from flat...at least compared to the Lectrsonics setup described above.


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Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: David Sturzenbecher on November 15, 2016, 07:05:58 pm

I would caution blindly using this approach.  The transfer function of this setup is far from flat...at least compared to the Lectrsonics setup described above.


See picture for some transfer functions a colleague of mine took.

Green - Loopback
Yellow - Lectrosonics Wireless Measurement Mic Test Equipment (HM Transmitter - R400a Receiver)
Purple - Shure Point to Point (UHF-R and PSM900)

Looks like the measurements were taken with -4dB as normalized.
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Luke Robinson on November 15, 2016, 08:18:55 pm
I looked at the specs for the Shure point to point, and though better than just using an IEM system alone it still says that its range tops out at around 1600ft, thats not quite enough for me. I think i found someone locally with the lectrosonics stuff, I am going to reach out tomorrow.

Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Roland Clarke on November 16, 2016, 07:27:36 am
We have a reoccurring gig each year that involves a parade of boats decorated for christmas on a river. This year we have been asked to transmit the audio from the announcer to both sides of the river. The second location is about 2500 ft from the first according to google maps.

We have clean line of sight and are elevated about 30-40 ft above the river on both sides.

Usually I use an IEM system for delay towers and the like but they seem to max out between 300 and 400 ft. I clearly need more power here.

Does anyone know of a solution for transmitting audio over this kind of distance cleanly?

Thanks,
Luke

Why don't you Podcast it or use Facebook live? This is half a mile, surely sync timing isn't that much of an issue?
Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: Tim Woodworth on November 16, 2016, 06:35:43 pm
We transmitted around 3500 ft. in one direction and 3500 ft. in the other direction. Covered over a mile by having our command center in the middle of the span needed to cover. Shure did an article about it on their website that I am sure you can find via google. I am sure that the spec that they say it will cover is a "safe" distance. We covered WAY more distance than that. We put the send and receive antennas up on genie towers so that we had line of sight to every tower and we had no issues and even had full bars on the zone that was 3500ft away.

Good luck!

Title: Re: Long distance (2500 ft) Wireless Audio Transmission
Post by: David Buckley on November 20, 2016, 04:41:39 pm
You should be able to find a rental house that has kit to do this, probably using equipment with significant output power, and they'll have the licensees to use it.  Also, you wont be in the whitespace bands where some other oik with a wireless mic near your receive antenna will wipe your link out.